Means for preventing overheating in aircraft deicing systems



.E. D. WHITE April 17, 1945.

MEANS FOR PREVENTING OVERHEATING IN AIRCRAFT DEIGING SYSTEM Filed March31, 1944 I INVENTOR ELMEQ 0. 1449/75 above the freezing point.

' J'ects and advan lines 2-2 of Fig. 1; and

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Patented Apr. 17, 1945 MEANS FOR PREVENTING OVERHEATING IN AIRCRAFTDEICING SYSTEMS Elmer D. White, Dayton, Ohio Application March 31, 1944,Serial No. 528,917

3 Claims.

The invention described herein may be manufactured and used by or forthe Government for governmental purposes, without the payment to me ofany royalty thereon.

This invention relates to means for preventing overheating in aircraftde-icing systemsfor wings and the like.

In existing wing de-icing systems, air entering a forward facing ram isheated by being passed through a heat exchanger and thenis led through aconduit or passageway adjacent the leading edge of the wing, which byconduction is heated far A considerable excess of heat must be conductedto the leading edge to insure quick melting of ice layers, which usuallybuild up with extreme-rapidity once the ice starts to form, and ifallowed to build up will force the to require no further (Granted underthe act or March amended April 30,1928; 370 0. G. 757) forced through aconduit II which extends to th leading edge of the wing and mayterminate at the wing tip as shown, where the heated air, now greatlycooled, will exhaust into the atmosphere.

The parts so far described are so well known as description orillustration.

According to the invention, an additional air ram I2, located on theleading edge of the wing preferably in the propeller slip stream, has aconduit I3 connecting with the conduit II, and thus causing aconsiderable volume of cold air to mix with the hot air passing throughconduit ll, thereby to reduce the temperature of the heated air to apoint where no damage to the wing can result. This mixing cold air withthe heated air is continuous and automatic, requiring no pilot toabandon his plane or attempt a crash landing. However, air at hightemperatures has damaging or even destructive effects on portions of thewing, which is necessarily made of thin metal or other light weightparts. This invention aims to provide a practicable construction andarrangement of parts which will permit adequate heating of the leadingedge of a wing, while obviating excessive or destructiveheating. Morespecific objects are to provide apparatus of the character indicatedwhich will not add materially to the weight of an airplane, which iseasily made and installed, which has few parts and none likely to giveservice troubles, which is automatic in action, and which requires fewchanges in the wing structure to permit installation. Other obtages willbe understood from the following description of the preferred embodimentof the invention shown in the accompanying drawing, wherein Fig. 1 is afragmentary plan view of an airplane wing equipped with apparatus forde-icing its leading edge, said apparatus being shown in dotted linesand includin the improvement herein claimed;

Fig. 2 is an enlarged vertical cross section on Fig. 3 is a sectiononline 3-3 of Fig. 2, but turned so that the in Fig. 3.

Referring particularly to the drawings. the illustrative airplane wing 5has a nacelle 6 housin an engine (not shown) and a cowling 1 adjacent apropeller, also not shown. A cold air intake 8 leads to an exhaust airheater 9, which is of conventional construction and requires no de- Theexhaust pipe 10 of the engine is also indicated. Air heated withinheater 9 is left end of Fig. 2 is uppermost power or manipulation ofcontrols etc., but takes place only Supported in slot I4 is a wirescreen I 5 which prevents insects, gravel etc. from entering the airconduit, and also facilitates the formation or a layer of ice when icingconditions exist. Once a layer of ice covers the screen, all flow ofcold air into conduit "ceases, and the heated air is undiluted withcooling air as it passes through conduit I I, hence the leading edge orthe airplane wing is subjected to the full heatin effect of the de-icingapparatus. This continues as longas the icing conditions persist; butwhen the airplane passes into another zone and icing no longer occurs,heat conducted from conduit l l to conduit l3 will be transferred toscreen l5 through the metal walls of the air inlet chamber l6 whichcon-. nects the air slot II with conduit clogging screen I! will thus beslowly melted, and the rush of air through the screen may hasten theremoval of the ice by carrying away or evaporating surface moisture.When the cold air starts flowing through erature of the conduit, l3 willimmediately drop and will continue to drop as the air inlet is furtheropened by melting of the ice. I 1

With the described apparatus, the pilot or engineer need only connectthe air heater when icing conditions are likely or possible, and theapparatus will automatically function as explained without any attentionor control. The attachment may be designed so as to be of light weightand will not detract materially from the performance of the airplane.

Obviously some changes may be made in the described apparatus, withinthe scope of the appended claims. In some instances additionalheat-conducting members may connect conduit H with the screen or itsmounting, so as to conwhile the passageway or slot I4 is open.

IS. The ice the air inlet ll, the temp-- eating with an air slot whichis formed at the leading edge of the wing and which discharges into theconduit when unobstructed; and means constructed and arranged to passair therethrough but facilitating the quick formation thereon of a layerof ice, such as will obstruct or prevent flow of air from the air slotthrough the duct into the conduit, whenever the aircraft enters an icingzone; said means being located at the entrance to the cold air duct andbeing formed of heatconducting material and being subjected to heatconducted from the hot air conduit so that ice forming thereon will beslowly removed by melting when the icing zone has been left behind.

2. The invention according to claim 1, wherein said means is a.metallicscreen of good heat conductivity.

3. In an aircraft wing de-icing system of the type employing a hot airconduit extending adjacent to the leading edge of the wing, thatimprovement which comprises a cold air inlet and conduit permanentlyconnected with the hot air conduit to continuously discharge cold airdirectly into the hot air conduit during flight of the aircraft throughnon-icing zones; and means in said inlet to facilitate quick building ofan airobstructing layer of ice within the inlet; said means beingheat-conductive and being located and supported so that a continuousflow of heat is conducted thereto from the hot air conduit but at a rateinsufficient to prevent building up of the ice layer when the aircraftencounters icing conditions.

- ELMER D. WHITE.

